1. Field of the Invention
This invention relates to the field of collection of biological fluids for diagnostic purposes. More particularly, the invention relates to the use of energy provided by an oscillating element to enhance the transdermal transport of biological fluids through human or animal skin.
2. Discussion of the Art
The prevalence of diabetes has been increasing markedly in the world.
At this time, diagnosed diabetics represented about 3% of the population of the United States. It is believed that the total actual number of diabetics in the United States is over 16,000,000. Diabetes can lead to numerous complications, such as, for example, retinopathy, nephropathy, and neuropathy.
The most important factor for reducing diabetes-associated complications is the maintenance of an appropriate level of glucose in the blood stream. The maintenance of the appropriate level of glucose in the blood stream may prevent and even reverse many of the effects of diabetes.
Glucose monitoring devices of the prior art have operated on the principle of taking blood from an individual by a variety of methods, such as by needle or lancet. An individual then coats a paper strip carrying chemistry with the blood, and finally insert the blood-coated strip into a blood glucose meter for measurement of glucose concentration by determination of change in reflectance.
There are numerous devices currently available for diabetics to monitor the level of blood glucose. The best of these devices require the diabetic to prick a finger and to collect a drop of blood for placement on a strip, which is inserted into a monitor that determines the level of glucose in the blood. Pricking one's finger tends to be painful. Moreover, a relatively large wound is produced by the pricking device, typically a lancet or a needle. It is known that the pain arising from the finger prick deters diabetics from compliance with the monitoring regimen. Lack of compliance increases the risk of complications due to diabetes. Thus there is a need for a more painless and less traumatic means of collecting biological samples for monitoring one's level of glucose in blood.
Ultrasound has been used to enhance the transdermal transport of biological fluids through human or animal skin. Eppstein et al, U.S. Pat. No. 5,458,140, discloses a method of enhancing the permeability of the skin or mucosa to an analyte for diagnostic purposes utilizing ultrasound or ultrasound plus a chemical enhancer. The ultrasound may be modified by means of frequency modulation, amplitude modulation, phase modulation, and/or combinations thereof. Lipkovker, U.S. Pat. No. 5,421,816, discloses a noninvasive method of withdrawing a fluid from an organism and determining the concentration of a substance in the fluid, said method comprising the steps of: (a) creating a cavity juxtaposed against the skin of said organism; (b) applying a focused beam of ultrasonic energy to the skin of said organism in the region of said cavity to cause fluid to be withdrawn into said cavity; and (c) analyzing fluid withdrawn into said cavity.